<p> In this report we explore how the effect of meteorological factors, allergens, and air pollution on respiratory conditions in children using longitudinal data. Our analysis makes use of a dataset from the DAVIS study in southern Ontario. The response variables are children's lower respiratory tract (URT) and upper respiratory tract (URT) scores. The explanatory variables are readings of various meteorological, allergen, and air pollution factors. First we make use of generalized estimating equations to find the main factors that are associated with certain respiratory conditions in children as measured by LRT and URT scores. Then we determine whether there are any interactions between the significant factors associated with LRT /URT scores. Comparisons between case and control groups are made to determine whether children with asthma are more sensitive to any of the changes in meteorological, allergen, and air pollution factors. The analysis results show that the significant factor that is associated with LRT scores for children with asthma is the two-day lag daily average changes in air pressure. On average an increase in air pressure will result in an increase in children's LRT scores. The interaction terms that remained in the final model show some degree of significance but without strong evidence to support it. Children in the case groups are more sensitive to meteorological factors, allergens, and air pollution than the children in control groups. </p> / Thesis / Master of Science (MSc)

<p> This study focuses on the relations hip between ice cover and wind frequency, wind speed and air temperature. Results showed that there are four distinct MELT periods along the west coast of Hudson Bay. With a standardized MELT period, stations are generally higher correlated with their southern neighbours. Onshore wind frequencies increased signficantly from the NOMELT to the MELT period, and were associated with air temperatures 3 to 4 degrees Celsius colder than those of offshore winds. </p> <p> Mean air temperature was most highly correlated with percent ice cover. Ice cover was most strongly correlated with mean air temperature at Chesterfield Inlet and least so at Churchill. Thus, freeze-up and melt at Chesterfield Inlet are most strongly influenced by air temperature whereas at Churchill, other factors, presumably wind direction and currents, strongly influence the ice cover. Ice cover was most strongly influenced by air temperature during the NOMELT period. This shows that cold temperatures hasten freezeback more than warm temperatures hasten MELT. </p> / Thesis / Bachelor of Arts (BA)

This study aims to investigate the influence of air pollutant concentration and meteorological factors on the atmospheric visibility in Taipei basin. First of all, we collected air quality data measured by ambient air quality monitoring stations of EPA (Environmental Protection Administration) and the meteorological factors monitored by Tamsui and Taipei meteorological stations separately, based on the range of three observation directions. We then analyzed the data by PCA (principal component analysis) to determine the main effective factors on atmospheric visibility under low visibility condition. In order to comprehend the spatial and temporal distribution of atmospheric visibility, we collected the atmospheric visibility data from Taipei meteorological observation stations for the past twenty-two years (1984~2005), it showed that the atmospheric visibility increased gradually. The seasonal variation of visibility was also observed, the best season was autumn (10.7 km) and the worst season was spring (7.5 km). Furthermore, according to the monthly statistical results, the visibility trends in the Taipei Basin can be separated into three typical periods: low visibility period (January to May), transitional period (June to September), high visibility period (October to December). The average atmospheric visibilities observed at the Tamsui, Songshan, and Sindian directions were 10.66 km , 9.54 km and 8.44 km, respectively. In general, the visibility at the Tamsui direction was slightly higher than those from other two directions. The results showed that atmospheric visibility was influenced not only by air pollutant levels and meteorological factors, but also affected by local topography of Taipei Basin. This study revealed that the atmospheric visibility data led on the Tamsui, Songshan observation directions is better. Four intensive observations of atmospheric visibility were conducted during March 28~April 1, July 4~8, September 19~23, and November 14~18 in the year of 2006, respectively. The results showed that the atmospheric visibilities at Tamsui direction were generally higher than other two directions. The visibilities observed in the afternoon were generally higher than those in the morning. Results obtained from the principle component analysis showed that the atmospheric visibility in the Taipei Basin were mainly influenced by PM10, NOx and CO, that mobile sources was the main cause of low visibility in the Taipei Basin. In addition, Tamsui region were affected by PM10 and SO2 more than Songshan and Sindian regions, which was influenced by neighboring industrial and the power plants. In the meteorological factors, wind speed and temperature have more influence on atmospheric visibility, however, the relationship between atmospheric visibility and relative humidity was somehow irregular. The analysis of the spatial distribution of air pollutants showed that low visibilities can not be caused only by high air pollutant concentration within the region, it may caused by the rise of air pollutant concentration in the transition region.

Ce travail de thèse a consisté à établir une base de données d'éboulements rocheux la plus exhaustive possible (pour des volumes supérieurs à 0,1 m3) pour une paroi rocheuse active dominant l'agglomération grenobloise, en utilisant des données de scanner laser et de photographie. Le site d'étude est une falaise calcaire de plusieurs kilomètres en bordure du massif de la Chartreuse, constituée de deux barres de morphologies différentes, l'une en calcaire lité, l'autre en calcaire massif.Les nuages de points issus du scanner laser permettent de reconstituer la falaise et les compartiments éboulés en 3D. Les données de surface des falaises, ainsi que des informations sur la localisation, les dimensions, le mécanisme de rupture propre à chaque compartiment ont été analysées pour caractériser l'évolution morphologique des deux falaises. Il apparait que la falaise inférieure, dont la morphologie dépend fortement de la fracturation et de l'érosion torrentielle des marnes sous-jacentes, présente une fréquence d'éboulement 22 fois plus importante que la falaise supérieure, de morphologie et pente régulière. De plus, dans la falaise inférieure, le taux d'érosion est 4 fois plus élevé entre 900 et 1000 m d'altitude, qu'entre 1000 et 1100 m. Cela montre que le régime d'érosion de cette falaise est transitoire, alors que celui de la falaise supérieure pourrait être permanent.Les éboulements rocheux détectés ont également été datés par un suivi photographique pendant 2,5 ans. Un suivi quasi-continu (1 photo toutes les 10 min), avec un objectif grand angle a permis de dater 214 éboulements de plus de 0,1 m3. Un suivi mensuel, avec un téléobjectif, a permis de dater 854 éboulements de plus de 0,01 m3. L'analyse de ces deux bases de données montre que la fréquence d'éboulements rocheux peut être 7 fois plus grande lors d'un épisode de gel-dégel que sans évènement météorologique particulier, et 4,5 fois plus grande lors d'un épisode de pluie. De plus, elle devient 26 fois plus grande si l'intensité depuis le début de l'épisode est supérieure à 5 mm/h. A partir de ces résultats, une échelle de 4 niveaux d'aléa a pu être proposée pour la prévision de l'aléa. La base de données plus précise et la définition des épisodes de gel-dégel ont permis de distinguer différentes phases dans un épisode de gel-dégel : refroidissement à température négative, réchauffement à température négative, et dégel (à température positive). Il apparait que les éboulements rocheux se produisent plus fréquemment lors des périodes de réchauffement (à température négative) et de dégel que lors des périodes de refroidissement. Cela suggère que les éboulements sont causés par la dilatation thermique de la glace plutôt que par la dilatation due au changement de phase. Ils peuvent cependant ne se produire que lors du dégel, car la cohésion de l'interface roche-glace peut être suffisante pour tenir le bloc jusqu'à la fonte de la glace. Des expériences in situ et en laboratoire ont permis de mesurer la pression de glace dans une fissure avec écoulement d'eau. Elles montrent que la glace formée par accrétion (gel de gouttes ou films d'eau) n'exerce pas de pression sur les parois rocheuses. / Using laser scanner data, an exhaustive rockfall database (for volume larger than 0.1 m3) has been established for a rockwall located near the town of Grenoble (France). The study site is a long double cliff, on the eastern border of the Chartreuse Massif. The two cliffs consist respectively of thinly bedded and massive limestone, which show different structures, morphologies and rockfall activities.The 3D point clouds obtained by laser scanner allow to detect and model the fallen compartments in 3D. Information about cliff surface, and localization, dimensions, failure mechanism for each compartment were obtained and analyzed in order to characterize the morphological evolutions of the two cliffs. It appears that the morphology and the slope of the lower cliff is related to fracturing and torrential erosion which occurs in the marls below the cliff. The rockfall frequency for this lower cliff is 22 times higher than for the upper cliff. Moreover, in the lower cliff the erosion rate is at least 4 times higher for an elevation between 900 and 1000 m than between 1000 and 1100 m. These results show that the erosion process in the lower cliff is in a transient state, whereas it could be in a steady state in the upper cliff. The morphology and the slope of the upper cliff is more regular than for the lower cliff.Rockfalls have been dated by photographic surveys during 2.5 years. A near-continuous survey (1 photo each 10 mn) with a wide-angle lens have allowed dating 214 rockfalls larger than 0.1 m3, and a monthly survey with a telephoto lens, dating 854 rockfalls larger than 0.01 m3. The analysis of the two data bases shows that the rockfall frequency is 7 times higher during freeze-thaw episodes than without meteorological event, and 4.5 times higher during rainfall episodes. Moreover, it becomes 26 times higher when the mean rainfall intensity (since the beginning of the rainfall episode) is higher than 5 mm/h. Based on these results, a 4-level hazard scale has been proposed for hazard prediction. The more precise data base and freeze-thaw episode definition make it possible to distinguish different phases in freeze-thaw episodes: negative temperature cooling periods, negative temperature warming periods and thawing periods. It appears that rockfalls occur more frequently during warming and thawing periods than during cooling periods. It can be inferred that rockfalls are caused by thermal ice dilatation rather than by dilatation due to the phase transition. But they may occur only when the ice melt, because the cohesion of the ice-rock interface can be sufficient to hold the failed rock compartment until the ice melt. The formation of ice in rock cracks has been studied in the field and in laboratory to highlight its influence on rockfall triggering. It has been shown that ice forming by an accretion process (freezing of water drops) doesn't exert a pressure on the crack walls.

Orientador: Francisco Jorge Cividanes / Banca: Antonio Carlos Busoli / Banca: José Maurício Simões Bento / Banca: Júlio César Galli / Banca: César Freire Carvalho / Resumo: Este foi conduzido no sul do estado da Bahia entre os anos de 2004 e 2007. Teve como objetivo determinar a taxa de fecundação de dendezeiros após a introdução de Elaeidobius kamerunicus Faust . Avaliaram-se as relações das espécies E. kamerunicus e Elaeidobius subvittatus Faust através da: flutuação populacional, distribuição espacial, influência de fatores meteorológicos, comportamento com relação às inflorescências das plantas e capacidade de transportar grãos de pólen. A taxa de fecundação nos dendezeiros atingiu 79,4%, representando incremento de 19% quando comparado aos dendezeiros polinizados apenas por E. subvittatus. Plantios comerciais de dendezeiros nos municípios de Taperoá e Nazaré, mostraram taxas de fecundação de 76,8% e 78,0%, respectivamente. E. kamerunicus foi a espécie dominante nos plantios de dendezeiro de Una, BA. Com exceção do município de Itapebi, as populações de E. kamerunicus sobrepujaram as de E. subvittatus em todos os municípios com grandes maciços de dendezeiros subespontâneos. A distribuição das chuvas no sul da Bahia não alterou a atividade polinizadora de E. kamerunicus, permitindo ocorrer taxa constante de fecundação dos frutos. Houve aumento da densidade populacional de E. subvittatus com o incremento térmico no ambiente ocorrendo o oposto com E. kamerunicus. O número de espécimes de E. subvittatus visitando inflorescências femininas de dendezeiros e híbridos interespecíficos foi superior ao de E. kamerunicus entre 6:00 e 8:00 horas, porém E. kamerunicus foi mais numeroso que E. subvittatus entre 9:00 e 12:00 horas. Essas espécies apresentaram pouca atividade polinizadora nas inflorescências femininas entre 14:00 e 16:00 horas, mas E. subvittatus congregou-se nas inflorescências femininas de ambas variedades de plantas a partir de 16:00 horas. Ao anoitecer foi constatada a presença... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The study was conducted in south Bahia between 2004 and 2007 to determine the rate of fertilization of oil palm after the introduction of Elaeidobius kamerunicus Faust in Southern Bahia. Relationships of the species E. kamerunicus and Elaeidobius subvittatus Faust were evaluated through population fluctuation, spatial distribution, influence of meteorological factors, behavior regarding the plant inflorescences and capability to collect and transport pollen grains. The data were analyzed utilizing correlation and variance analysis and test of means. The rate of fertilization in the oil palm trees reached 79.4%, representing an increase of 19% when compared to oil palm trees pollinated only by E. subvittatus. Commercial plantations of oil palm trees in Taperoá and Nazareth municipalities showed rates of fertilization of 76.8% and 78.0%, respectively. E. kamerunicus was the dominant species in the plantations of oil palm trees of Una, BA. With the exception of Itapebi municipality, the populations of E. kamerunicus overwhelmed the E. subvittatus in all municipalities with large plantations of sub-spontaneous oil palm trees. The rainfall distribution in south Bahia did not alter the pollination activity of E. kamerunicus, which permitted a constant rate of fruit fertilization. There was an increase in population density of E. subvittatus with environmental thermal increase, the opposite occurred with E. kamerunicus. The number of specimens of E. subvittatus visiting female inflorescences of oil palm trees and interspecific hybrids was higher than that of E. kamerunicus between 6:00 and 8:00 hours, however E. kamerunicus was more numerous than E. subvittatus between 9:00 and 12:00 hours. These species presented little pollination activity in female inflorescences between 14:00 and 16:00 hours, but E. subvittatus congregated in the female inflorescences of both oil palm varieties starting ...(Complete abstract click electronic access below) / Doutor

Orientador: Júlio César Galli / Banca: Arlindo Leal Boiça Júnior / Banca: Valter Arthur / Resumo: Considerando-se a importância de estudos relacionados à entomofauna em pomares de goiaba para o manejo integrado de pragas, o presente trabalho objetivou: a-) Conhecer a entomofauna associada à parte aérea através do uso de armadilhas adesivas amarelas em pomar comercial de goiaba com uso predominante do inseticida imidacloprid na região de Vista Alegre do Alto-SP e em pomar experimental semi-orgânico de goiaba na região de Pindorama-SP; b-) Conhecer as flutuações populacionais dos insetos principais (pragas e inimigos naturais) em ambos os pomares e as correlações com dados meteorológicos das duas regiões. Para levantamento da dinâmica populacional, os espécimes foram coletados com armadilhas adesivas amarelas (25 cm x 9,5 cm), trocadas a cada 15 dias. Os experimentos foram realizados entre março e novembro de 2009 em Vista Alegre do Alto-SP, e entre junho de 2009 e junho de 2010 em Pindorama-SP. Com base nos resultados obtidos e nas condições de desenvolvimento do presente projeto, foi possível obter as seguintes conclusões: a) As maiores densidades populacionais de Triozoida limbata ocorrem em outubro e novembro e as menores em março e abril, sendo esta a principal praga em pomar comercial em Vista Alegre do Alto-SP; b) As maiores densidades de T. limbata ocorrem em setembro e as menores ocorrem entre junho e agosto em Pindorama-SP; c) Ceratites capitata é a espécie de tefritídeo de maior ocorrência em Vista Alegre do Alto-SP e Anastrepha spp. é o gênero predominante e a principal praga em Pindorama- SP; d) Anastrepha spp. apresenta correlação significativa pelos fatores meteorológicos: temperaturas mínima, média e máxima (0C) em Pindorama-SP; e) Scymnus spp. é o inimigo natural com maior número de indivíduos coletados com armadilhas adesivas amarelas em Vista Alegre do Alto e Pindorama-SP; f) As maiores ocorrências de Scymnus spp. são nos meses de abril... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Considering the importance of studies related to entomofauna in orchards guava for integrated pest management, the present study aimed: a-)To know the insects associated with shoot through the use of yellow sticky traps in commercial guava orchard with predominant use of imidacloprid insecticide in the region of Vista Alegre do Alto-SP and semi-organic experimental guava orchard in the region of Pindorama-SP; b-) To know the major population fluctuations of main insects (pests and natural enemies) on both orchards and the correlations with meteorological data from the two regions. To perform the survey of the population dynamics, the specimens have been collected with yellow sticky traps (25 cm x 9.5 cm), replaced every 15 days. The experiments was conducted between March and November (2009) in Vista Alegre do Alto-SP and between June (2009) and June (2010) in Pindorama-SP. Based on the results obtained and the conditions of development of this project, it was possible to obtain the following conclusions: a) The highest densities of Triozoida limbata occur in October and November and the lowest in March and April, being this the main pest in commercial orchards in Vista Alegre do Alto-SP; b) The highest densities of T. limbata occur in September and the lowest occur between June and August in Pindorama-SP; c) Ceratites capitata is the specie of tephritid prevailing in Vista Alegre do Alto and Anastrepha spp. is the genus predominant and the main pest in Pindorama-SP; d) Anastrepha spp. has presented significant correlation with the meteorological factors: minimum, average and maximum temperatures (0C) in Pindorama-SP; e) Scymnus spp. is the natural enemy with the greatest number of individuals collected with the yellow sticky traps in Vista Alegre do Alto-SP and Pindorama-SP; f) The highest occurrences of Scymnus spp. are in the months of April and May and the lowest densities occur... (Complete abstract click electronic access below) / Mestre

Prior research has shown pathogen prevalence on-farms is not uniformly distributed, instead pathogen prevalence is highly dependent on environmental factors and management practices. A study was performed to determine environmental factors (e.g., landscape features, meteorological events) and management practices (e.g., date of last irrigation, pesticide application) that may impact the prevalence of Salmonella spp. and Listeria spp. at the sub-field level (0.2 ha grids) on an Eastern Shore of Virginia farm. Virginia Tech's Eastern Shore Agricultural Research and Extension Center (ESAREC) farm was used due to the liability of testing for pathogens in commercial produce fields; however, production practices used at the ESAREC farm are similar, if not the same, to production practices used on commercial farms. Fifteen drag swab, one water, and up to five fecal samples were collected every two weeks per sampling occurrence from August to December 2016 (thus up to 21 samples may be collected during one sampling occurrence. Samples were collected from randomized field plots that were picked during each sampling occurrence. Salmonella spp. and Listeria spp. were isolated and confirmed using modified versions of the Food and Drug Administration's Bacteriological Analytical Manual. Environmental factors were retrieved by remotely-sensed data for the sample location or date. Management practices were recorded by an observational survey for each sample occurrence. Two hundred and seventy-four samples (210 drag swab, 50 fecal, and 14 water samples) were collected during the late summer, fall, and winter. Listeria spp. and Salmonella spp. was detected in 8.3% (23/274) and 1.8% (5/274) of samples, respectively. Neither pathogen was detected in any of the fourteen water samples tested. Findings from this study will support the development of mitigation strategies to reduce pathogen contamination on-farm, with emphasis at the sub-field level. For instance, mitigation strategies include growers electing to not harvest near edges of fields or directly after precipitation events to minimize contamination events. Additionally, management practices were found to be associated with pathogen prevalence; therefore, management practices should be carefully tailored for each unique farm landscape. / Master of Science in Life Sciences

Falls and their consequences are a major health problem in the older population, increasing their immobility, morbidity and mortality. This thesis focuses on older people living in geriatric care settings, frail older people who are most prone to suffer falls. The aim was to study predisposing and precipitating factors associated with falls in older people with or without cognitive impairment. In a cross-sectional study with a one-year prospective follow-up for falls 63% of the 83 residents suffered 163 falls and 65% of the fallers fell more than once. The antidepressants selective serotonine reuptake inhibitors (SSRIs), impaired vision and being unable to use stairs independently were the factors most strongly associated with sustaining falls. Acute diseases were judged to have precipitated 32 % of the falls and drug side effects 9%. In another cross-sectional study with a one-year follow-up for falls, including 199 residents, previous falls and treatment with antidepressants (mainly SSRIs) were found to be the most important predisposing factor for falls. Acute disease was judged to be the precipitating factor alone or in combination, in 39% of the falls, medical drugs in 8%, external factors such as obstacles in 8% and other conditions both related to the individual and the environment, such as misinterpretation, misuse of roller walkers or mistakes made by the staff were judged to have precipitated 17% of the falls. In a population-based cross-sectional study including 3604 residents in geriatric care settings more than 8% sustained a fall at least once during the preceding week. A history of falls, the ability to get up from a chair, the need for a helper when walking, pain, cognitive impairment, use of neuroleptics and use of antidepressants were all associated with falls in multivariate analyses. In the subgroup of people with cognitive impairment (2008 residents) more than 9% had sustained a fall at least once during the preceding week. As for the whole population, being able to get up from a chair, previous falls, needing a helper when walking with the addition of hyperactive symptoms were the factors independently associated with falls. In a study with a one-year prospective follow up for falls, including 439 residents in residential care facilities, 63% sustained 1354 falls, corresponding to an incidence rate of 3.5 falls / person year. Thirty-three percent of the falls and 37% of the injurious falls occurred during the night (9pm-6am). There were significantly higher fall rates in the evening and in January, April, May, November and December. There were no associations between fall rates and any of the weather parameters studied. In conclusion falls and fall-related injuries in older people in geriatric care settings are common. Both predisposing and precipitating factors contribute to the risk of falling. Addressing precipitating factors for falls seems to be important in an individualised preventive strategy among older people in geriatric care settings.

Spatial and temporal variations and factors affecting these variations in concentrations of measured parameters at two different groups of stations in Ankara are investigated in this study. The first group consists of three curbside stations that are under the direct influence of traffic emissions, on the other hand, the other group is composed of eight residential stations in which domestic heating is the main emission source. State of air quality in Ankara is determined through comparison with air quality data generated in other countries and available air quality standards. Based on this comparison, although air quality has improved in recent years, it is still not one of the clean cities around the world. Although measured concentrations of pollutants comply with standards in the Turkish Air Quality Regulation, further reduction in concentrations will be necessary, if EU directives become effective in the country. Relation between measured concentrations and meteorological parameters are also investigated. Wind speed and mixing height are the two parameters that are most closely related to measured concentrations at residential stations. However, at curbside stations concentrations are determined by emissions. Qualitative comparison of two groups of stations emphasizes the contribution of motor vehicle emissions on residential areas. Seasonal and diurnal variations of measured parameters and lower winter-to-summer ratio of SO2 indicate contribution of diesel vehicle emissions to SO2 levels at curbside stations. Contribution of traffic emissions are also observed in terms of well defined bimodal traffic pattern of SO2 and PM-10 at non-curbside stations. Seasonal and diurnal pollutant ratios are investigated to apportion different source types that are effective in each group of station. PM-to-SO2, NO-to-NO2, PM-10-to-NOX and SO2-to-NOX ratios are found to be good tracers for qualitative assessment of source groups, namely traffic and domestic heating. Different statistical methodologies are demonstrated to determine the source regions of pollutants with respect to wind direction. Air quality level of Ankara, instead of air quality level in each station, is determined in terms of daily API. One by one correlation between API and meteorological factors are investigated, maximum wind speed and daily thermic excursion is found to be the highest correlated variables. The relation between API and these variables is analyzed by multiple linear regression method and then air pollution forecast model highly correlated with API and meteorological variables is developed. The assimilative capacity of Ankara is calculated in terms of ventilation coefficient and found to be highest in summer and lowest in winter. In winter poor dispersion conditions favor the poor air quality in the city.

The predominant campestral vegetation in the state of Rio Grande do Sul, as well as all types of vegetal formations, may be considered as a dynamic system subject to several disturbance agents. Fire is frequently mentioned as one of them, and may present natural or anthropic causes. Occasional burns are mainly a result of electric discharges from the atmosphere. Intentional burns may be controlled or not and are usually associated to the management of areas aimed at agriculture and cattle raising activities. Thus, the objective of this research was to perform a study on accidental field burns in order to characterize and to identify places of higher burn incidence in the county of Santa Maria RS, Brazil, and to aid in the planning and control of fires, correlating the number of burns with meteorological elements in order to identify the most propitious conditions for the occurrence of these events. The interest variable (response) in this study was the number of daily calls received by the Santa Maria Fire Brigade obtained from its records within the period from January 1st 1993 to December 31st 2004. This variable was explained by meteorological elements such as: maximum and minimum temperature; relative air humidity measured at 9:00am, 3:00pm and 9:00pm; insolation; rain precipitation and average wind velocity at the day of occurrence and by the number of days without any pluviometric precipitation before the occurrence of the interest variable. It was verified that the Fire Brigade received 1.81 daily calls, on average; that the call was preceded by a dry period of four days on average, and that most burns occurred in the afternoon and at the almost uninhabited RS 287 highway alongside region. The month in which the Fire Brigade received the highest number of calls was August, and the year of 1999 was the one presenting the highest occurrence of field burns. Moreover, the number of calls was equally distributed along the weekdays. Based on quartiles, city districts with high, intermediate and low chances for the occurrence of burns were determined, and regions alongside the highway and the following city districts: Distrito Industrial, Medianeira, Itararé, Tomazzetti and Parque Pinheiro Machado were those presenting the highest chances for the occurrence of burns. Based on the correlation between dependent variable and all independent variables, it was verified that the variable with the highest correlation with the number of calls received by the Fire Brigade was the relative air humidity. The evaluation of the twenty-four models tested revealed that in all of them, the presuppositions were violated, being therefore, inappropriate for the forecast of the independent variable. / A vegetação campestre, predominante no Rio Grande do Sul, bem como todos os demais tipos de formações vegetais, pode ser considerada um sistema dinâmico sujeito a uma série de agentes de perturbações. O fogo costuma ser citado como um destes, podendo ser de causa natural ou provocado pelo homem. As queimadas casuais são resultantes, em especial, de descargas elétricas da atmosfera. Queimas provocadas podem apresentar-se controladas ou não e costumam estar vinculadas ao manejo de áreas utilizadas em fins agropecuários. Desta forma, esta pesquisa teve como objetivos realizar um estudo de queimadas acidentais em campo para identificar, caracterizar e localizar os locais de maiores ocorrências dessas na cidade de Santa Maria - RS com intuito de auxiliar no planejamento e controle de incêndios, relacionar o número de queimadas com os elementos meteorológicos para identificar as condições mais propícias à ocorrência desse evento. A variável de interesse (resposta), neste estudo, foi o número de chamadas recebidas por dia pelo Corpo de Bombeiros de Santa Maria, obtidas dos seus fichários, no período de 1º de janeiro de 1993 a 31 de dezembro de 2004. Essa variável foi explicada por elementos meteorológicos, como: temperatura máxima e mínima, umidade relativa do ar coletada às 9 h, às 15 h e às 21 h, insolação, precipitação e velocidade média do vento do dia de sua ocorrência e pelo número de dias sem precipitação pluviométrica, anteriores ao da ocorrência da variável de interesse. Verificou-se que em média o Corpo de Bombeiros recebia 1,81 chamadas diárias. Antes da ocorrência de uma chamada, não chovia, em média, a quatro dias, e a grande maioria das chamadas eram no período da tarde e para as margens das rodovias que circundam a cidade, principalmente na RS 287, rodovia com margens pouco habitadas. O mês em que ocorreu o maior número de chamadas ao Corpo de Bombeiros foi agosto, sendo o ano de 1999 o que acumulou maior ocorrência de queimadas. Além disso, o número de chamadas distribuem-se equivalentemente nos dias de semana. A partir dos quartis, determinou-se os bairros do município com grande, média e poucas chances de ocorrência de queimadas, sendo que as margens das rodovias e os bairros Distrito Industrial, Medianeira, Itararé, Tomazzetti e Parque Pinheiro Machado foram as áreas com maiores chances de ocorrência de queimadas. Determinada a correlação entre a variável dependente e todas as variáveis independentes, verificou-se que a mais correlacionada com o número de chamadas recebidas pelo Corpo de Bombeiros foi a umidade relativa média. A avaliação dos pressupostos dos vinte e quatro modelos testados, revelou que em todos eles as pressuposições foram violadas, não sendo portanto, adequados à previsão da variável independente.